Plongée & conservation marine Thaïlande - Rapport mensuel
Conservation in Thailand - Monthly Update February 2008
I ended January's update by mentioning 2008 was International Year of the Reef (IYOR), which is a worldwide drive to raise environmental awareness about coral reefs and the threats they face, and to encourage conservation activities from all sectors of society to help preserve the reef ecosystems. We have adopted Mu Sang Nua as our reef to protect over the year, so in the middle of February we made our first trip there to search for any fishing nets or salvage. We came across two nets very near the surface which made them quite difficult to remove due to strong surface waves and currents, and the need for extra good buoyancy control. However, the volunteers did manage to remove 20kg of net, which along with the glass bottles, cans and a fish trap that we collected from other reefs gives a monthly total of 27kg.
In addition to keeping the reef clean, we have decided to carry out a detailed coral and fish diversity study, with an aim of compiling an end of year report to try to persuade the authorities to offer more protection for this beautiful reef. Consequently, whilst the volunteers were cutting away the net, I swam over the reef taking as many photos as possible to identify later with the help of the fish and coral books on board the boat. Of particular note was an unidentified seahorse that I found attached to a sea fan. We have looked through the books and also on websites such as ReefBase but could not find a matching description; we will continue our search.
Another plan we have for Mu Sang Nua, as well as some other reefs that we visit regularly, is to lay down permanent transects so we can return to the same spot each time to carry out repeated fish censuses and build up time lapse photography records of the reef along the line. The method we intend to use is to drive two metal stakes into the seabed, 50 metres apart which we will leave there permanently and attach a rope each time we return to swim along, carrying out surveys. To lay the transect for the first time we need good sea conditions, so we aim to return to Mu Sang Nua again on a day of neap tides during March to do this, and of course, to also remove anymore nets if we find them. In February, we did manage to put stakes into two reefs, Maya Bay and Ao Nui, which is a good start to this development in our reef monitoring activities. Over the coming months we hope to lay transects on four or five local reefs, and the same number around Phi Phi.
At the end of January we were approached by the Krabi Fisheries Department, based in Ao Nam Mao, who asked us to help them release some of the fish they have been breeding. They have in the region of 20,000 damsel fish and a few hundred anemonefish ready for release, so on three days during February we collected bags with juvenile damsel fish inside, and released them on to four local reefs and at two reefs on Phi Phi. Each bag held fifty fish and we released an average of four hundred on each reef. The three species released were the Bengal sergeant (Abudefduf bengalensis), Lemon damsel (Pomacentrus moluccensis) and the Similar damsel (Pomacentrus similis). We knew it was important to open the bags as close to the reef as possible rather than high up in the water column, as this gave the fish better chance to quickly hide amongst the corals rather than being preyed upon immediately. We also discovered that the branching staghorn corals (Acropora sp) were the most suitable as the spreading branches offered the most protection for the young fish. Although damsels are numerous on the reefs already, they form part of the food chain so breeding and releasing them has benefit for the local reef ecosystem.
Another subsea activity that we have learnt about and participated in this month is the monitoring of coral disease. An American marine scientist based at Phuket Marine Biological Centre, Carly Kenkel, is carrying out baseline surveys of disease affecting corals in Thailand, since to date there has been very little research in this field. Last week, she came to Ao Nang and gave us an interesting presentation on the rise of coral diseases since the first case was observed in the Caribbean during the 1970's, the state of Thailand's corals and the results of her research so far. The following day we all went to two reefs on Phi Phi Don where she had observed a presence of both White Syndrome and Porites Pinking, the two main diseases she had noted. She showed us the types of corals that these diseases were commonly found in and then pointed out examples of each when she encountered them. The White Syndrome was quite hard to distinguish from coral bleaching and predation, but the Porites Pinking was glaringly obvious when pointed out since it looked like the coral had been sprayed with a can of pink paint. The next day we went to two reefs that Carly had not surveyed, Mushroom Rock and Ao Nui, where we carried out 30 minute timed swim surveys noting down any disease we observed. However, both reefs turned out to be pretty healthy in terms of disease with only two cases spotted on each reef. In comparison to the two reefs we visited the previous day for the training which had numerous infected corals, this was a positive sign. The surveys on the second day were useful for Carly as they were new sites for her, and it was good for us to put into practice what we had learnt. It was also exciting to be involved in an area of research that is very new in Thailand, and we hope to help her investigations in the future by informing her whenever we see instances of disease.
February has been another great month for marine organism sightings, with volunteers observing one Green and one Hawksbill turtle, two Leopard sharks, two Banded seasnakes, a well camouflaged Leopard flounder flat in the sand, a Peacock mantis shrimp, the biggest nudibranch I have ever seen here, and three pipefish that look very similar to the Messmate pipefish. However, its geographical distribution does not correspond with this region, normally being found within the Pacific reaching as far as Indonesia. It is probable that our id books are not fully comprehensive for the seahorses and pipefishes found in the Andaman Sea, and that it is just a close relation to the Messmate pipefish. Even more exciting has been the sighting of two species of fish that are very rare on the reefs around here, to the extent that I had not seen either until now and had thought that they had been fished to extinction in Krabi. The first was a Bumphead parrotfish (Bulbometopon muricatum) at Bida Nai and the other a Napoleon or Humphead wrasse (Cheilinus undulates) at Koh Ya Wa Sam. Both are large fish and would be quite a catch for any fisherman. Fishing is a particular threat for the Napoleon wrasse as it takes many years for it to reach maturity so may be caught before it can breed, and is consequently globally endangered; let's hope it can defy the fishermen's nets for years to come.
On to the land based side of the project where there have been three beach cleans and four days in the mangroves. The beaches were Ao Thung, Ao Nam Mao and Lam Pho Village beach, from which we removed a total on 789kg. At Ao Thung we dug four tyres out of the sand, one of which must have been from a monster truck as it was almost bigger than any of us. Although we had cleaned the beach at Lam Pho Village a month before, we found it was just as dirty as the previous visit, which we were initially shocked by. However, on looking at the map and seeing the orientation of the beach, I realised a lot of the rubbish washed down the Krabi River must have been blown on to this beach by the easterly monsoon winds, so we will no doubt have to return to clean again before the start of the rainy season and the change in wind direction.
The days in the mangroves have been mostly taken up by land clearance this month, both clearing an area at Baan Thung Prasan for future replanting with the local community, and also extending the range of our research nursery in preparation for continuing our experiments. In March, we hope to transplant the Bruguiera sexangula saplings using the same methods as the Ceriops tagal trees that we moved in January. On another day we returned to Wat Pakasai, the temple where volunteers had planted 1,300 saplings in November last year. After doing a little clearance of weeds in order to find the planted trees, we estimated the overall survival rate to be between 60-70%, which we were very happy to observe.
So, despite February being the shortest month of the year, it has been an interesting month where we have made progress in all areas of the project. In March, we will continue with the aims of IYOR, with plans to develop educational posters to spread around the tour agencies and hotels in Ao Nang, trying to raise the environmental awareness of the tourists that visit this area. The rise in tourism, and the consequent increase in coastal development and tourist activities that put pressure on the fragile reef ecosystems, is undoubtedly having a negative impact on the coral reefs, so we really hope that the posters and fliers that we develop helps to enlighten the tourists on how they can look after the reefs.
Click here and see our graphs of the amount of rubbish the volunteers have collected from the reefs and beaches here in Ao Nang in February 2008 - impressive work.
Click here and see our graphs of the amount of rubbish the volunteers have collected from the reefs and beaches here in Ao Nang over 2007 - impressive work.
4th March 2008
Director for Thailand Conservation